Answer
Clean the surface, use controlled strokes, and refine one grit at a time.
Why it happens
Random sanding direction, debris, or inconsistent pressure can leave visible marks.
Recommended grit
Return to the previous effective grit, then refine with the next finer grit.
Wet or dry
Dry for prep; wet for fine finishing stages.
Success check
Random swirl marks are replaced by a controlled, even scratch pattern.
What to do
- Clean the surface and sheet.
- Sand in controlled strokes.
- Move to the next finer grit only after marks are even.
- Inspect under angled light.
Avoid: Do not drag debris across the surface.